Golf ball



ch 30, 1944. K. E. WILHELM 2,360,090

GOLF BALL Filed Oct. 2 1942 AT TOHNEY Patented Oct. 10,1944

United States'ltubber Company, New

N. Y., a corporation of New Jersey York,

Application fictober 2, 1942, Serial No. 450,540

2 Claims. (Cl. 273-62) vide a harder ball having greater night.

This increase in the thread tension has caused a tendency of the ball to go .out of round when in use, and which apparently is caused by the rupture of the thread windings adjacent the-rubber center in a localized area of the ball.

It is known that this tendency of a ball to go out of round is avoided by using a very hard rubber or celluloid center, but this causes the ball to have a woody feel when struck with the club, it also increases the tendency-of the windings lying next to the center to slip on the hard smooth surface, and the cover is more likely to cut when the ball center is very hard. The tendency of a ball to go out of round is also avoided by using a liquid or mobile center, but

the liquid has to be confined'in someform of envelope which adds to the cost of manufacture.

It is believed that the tendency of a ball to go out of round when-it is provided with a semi-' hard rubber center is due, at least in part, to

the fact that the elastic properties of such center exert an injurious action upon the thread windings adiacerit the center when the ball is struck' hard.

The primary purpose of the present invention is to provide a golf ball witha semi-hard plastic or plastic-like center which will increase the life of the golf ball over that of a ball having. a semihard rubber center, without reducing the flight of the ball or its other desired properties.

Since, as above stated, I believe that the elastic properties of a semi-hard rubber center act injuriously upon the thread windings adjacent the center, I propose to overcome this difficulty by material forming the center will gradually penetrate into the interstices between the thread windings, and that the windings engaging the center shall sink into its surface sufficiently to equalize the forces acting upon the threads so as to avoid .unduly stressing any of these threads.

The golf ball center or core contemplated by the present invention can be formed of any one of a large number of highly plasticized plastics and also of plastic-like material, provided they are moderately hard and have good cold flow properties. Theball body and cover may .be constructed as usual heretofore.

The various features of the present invention will be more fully understoodfrom the following description when read in connection with the accompanying drawing wherein:

Fig. 1 is a front elevation with parts in section of a golf ball having the construction of the present invention; and

, Fig. 2 is an enlarged sectional view taken on the line 2-2 of Fig. 1.

The golf ball shown in the drawing may be of usual construction except for the material forming the center and as illustrated comprises a center l0 and body I I, the latter being formed by winding a thread or tape l2 of rubber or other strand forming material tightly about the center. The ball body ll isyenclosed in a cover l3 which may be formed of balata in accordance with the usual practice. The size of the center In may be tively'high cold flow so that the material forming the center will flow between the thread windings as indicated by M. It is also important that the elastic properties of the center l0 shall be employing a semi-hard center having low elastic V properties and substantial cold flow so that when the center is suddenly deformed it will recover slowly.

It is extremely important in carrying out the present invention that the center employed shall have pronounced cold flow properties at ordinary temperatures so. that the plastic or plastic-like considerably below that of the elastic properties of the semi-hard rubber center commonly used heretofore in golf balls.

The present golf ball center I 0, as above stated, maybe made of any one of a large number of highly plasticized plastics having the low elastic .properties and pronounced cold flow herein contemplated. and the center may also be formed of plastic-like material possessing these properties.

The preferred class of materials which may .be employed in making up the present center .ineludes highly plasticized plastics such as polyvinylbutyral, ethyl cellulose, cellulose acetate,

nitrocellulose, and the various types of vinylites.

The center ll may also be formed of plastic-like materials such. as a mixture of ground rubber scrap and a relatively soft viscous bonding materia1 such as stearine pitch-provided the resulting material has the desired degrees of hardness and the cold flow properties above mentioned.

These center forming materials may have their properties modified by the addition of plasticizers, fillers and the like.

In order to secure the desired degree oi cold flow under the pressure of the thread windings, it is believed that the material forming the center should have a hardness range between 25 and 60 on a'shore A durometer scale whenthe reading In each of these examples the parts when ther oughly mixed form a plastic-like mass having very little elasticity but high cold ilow properties,

' and a hardness within the range above 'mentioned. A golf ball center, formed of the material of either of the above examples, when dropped from a distanceonto a hard surface had very little ability to rebound.

Golf balls provided with centers made up of the material of Example I and of the material 01' Example II when tested for durability were found to stand up better than similar golf. balls,

having a semi-hard rubber center. 7

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. A golf ball having a center formed primarily of a plasticized thermoplastic resin and possessing very little ability to rebound but having high cold flow properties, and a body formed of threads wound tightly around thecenter in direct contact with the center forming material, the material 01' the center having a hardness range between 25 and .60 on ashore A durometer scale when the'reading is taken ten seconds after the application of the pressure, the said cold flow properties of the center being sufflciently high at room temperature to cause the material of the center to penetrate gradually but deeply into the interstices-between the threads and flow about the threads into accurate molding relation therewith. Y

2. Agoli ballhaving a center i'ormed primarily of plasticized polyvinyl butyral and possessing very-little elasticity and very little ability to re bound but having high cold flow properties, and a body formed of threads-wound tightly around the center in direct contact with the center forming material, the material of the center havin a hardness range between 25 and 60 one Shore A durometer scale when thereading is taken ten seconds after the application of the pressure, the

said cold flow properties of the center being suillciently high at room temperature to cause the material of the center to penetrate gradually but deeply into the interstices between the threads and now aboutthe threads into accurate mold ing relation therewith.

- KURT E. wnmznu. 

